Priming mixture



i Patented EDMUND VON HERZ, OF COLOGNE-DELLBRUGK, GERMANY, ASSIGNOR TO REMINGTON ARMS COMPANY, INC., A CORPORATION OF DELAWARE PRIMING MIXTURE No Drawing.

'at a comparatively low temperature, has in the past been quite universally used as a priming mixture oxidizer. The elimination of the corrosive potassium chlorate necessitates the substitution of an oxidizer which does not yield its oxygen with the same facility as potassium chlorate. Higher temperatures are required to render the oxygen available, or a larger amount of the oxidizer in order to furnish an equivalent amount of oxygen with an incomplete yield. Barium nitrate, for example, contains a relatively large amount of oxygen, but it becomes available only at temperatures substantially higher than those. necessary to completely decompose potassium chlorate. The necessity for higher temperatures has been met in general by the increase in the quantity of the initial explosive, which is generally mercury reason of both the cost and the poisonous character of mercury fulminate, and for the further reasons which will be briefly considered.

Mercury iulminate detonates under the impact of the firing pin but this action being an instantaneous detonation and not combustion does not produce a sustained flame. The result is that the temperature may not be raised sufiiciently to effect the proper reaction between the fuel and the somewhat sluggish oxidizer. Increasing the fulminate content merely serves to increase the force of detonation but not to appreciably increase the duration of the accompanying flame, and furthermore the forceful detonation of the large quantity of mercury fulminate may cause pierced or blown primers and burst cases, without efiectin g proper ignition. The

Application filed January 5, 1929. Serial No. 330,622.

flame of the detonatingmercury fulminate is insuiiicient to ignite propellant powder, and the other ingredients react slowly, incompletely and with a poor flame. The powder ignition is slow and irregular, resulting in hangfires and incomplete combustion.

A great improvement is effected when a part of the mercury fulminateis replaced by another explosive such as lead trinitroresorcinate. This substance is less sensitive to blows, such as the impact of a firing pin, than mercury fulminate, but is readily decomposed by the shock resulting fromv the detonation of the mercury fulminate and its decomposition is accompanied by a long and well sustained flame. This effect may be due to the fact that the decomposition results in a great deal more free carbon than the decomposition of mercury fulminate and the excess of nascent carbon by reason of its afiinity for oxygen initiates the decomposition of the barium nitrate which proceeds to completion great afiinity for oxygen, such for example,

as antimony sulphide. The carbon being present in a nascent state owing to the decomposition of the lead trinitroresorcinate will be completely oxidized first, and only the oxygen remaining after such complete oxidation is available for the oxidation of antimony sulphide, the constituents of which do not have a very great afiinity for oxygen. The large amount of mercury fulminate and oxidizer necessary limit the antimony sulphide to an amount insuflicient to produce the incandescent particles necessary for proper powder ignition.

The present invention comprises the discovery that calcium silicide possesses properties which render it especially desirable as a fuel for priming mixtures of the type heretofore discussed. The constituents of this compound, calcium and silicon, both have a very great afiinity for oxygen. The substance is very hard and once ignited projects out incandescent particles well adapted to traverse the propellant powder and effect uniform and thorough ignitlon thereof. The great af-' finity of calcium silicide for oxygen and its capacity for emitting incandescent particles is strikingly illustrated by the fact that a mixture of calcium silicide with barium nitrate can be ignited with comparative ease, and its combustion is accompanied by a shower of sparks.

Some examples of non-corrosive priming mixtures using calcium silicide as a fuel are as follows:

The use of a small amount of lead peroxide is desirable, on account of the ease with which it combines with calcium silicide, the resulting heat facilitating the decomposition of barium nitrate. It is desirable, however, that the amount of lead peroxide be small, say not V greater than 10% or 12% of the mixture.

In mixtures of this type it is necessary to provide only enough oxidizer to oxidize the calcium silicide, since this oxidation takes place before that of the carbon liberated by the mercury fulminate and lead trinitroresorcinate. It has even been found possible toomit the mercury fulminate, or to replace it with other known initial explosives. Typical non-fulminate formulas are as follows:

Per cent Lead trinitroresorcinate 4O Barium nitrate 35 Calcium silicide Lead peroxide 5 and Per cent Lead trinitroresorcinate Barium nitrate Calcium silicide -4 25 In these compositions a part of the lead trinitroresorcinate may be replaced by another initial explosive, and many other variations may be-made, all within the scope of the appended claims.

What is claimed is:

1. A priming mixture for ammunition containing silicide. 2. A priming mixture for ammunition containing mercury fulminate, lead trinitroresorcinate and calcium silicide.

lead trinitroresorcinate and calcium 3. A priming mixture for ammunition containing mercury fulminate, lead tri.nitro-.v

resorcinate, barium nitrate and calcium silicide.

6. A. priming mixture for ammunition containing mercury fulminate, lead trinitronate, 12% to 25 of calcium silicide and 25% to 40% of barium nitrate.

10. A priming mixture for ammunition containing 15% to 25% mercury fulminate, 25% to lead trinitroresorcinate, 28% to barium nitrate and 12% to 15% calcium silicide. r

11. A priming mixture for ammunition containing 15% to 25% mercury fulminate, 25% to 30% lead trinitroresorcinate, 28% to 40% barium nitrate and 5% to 8% lead peroxide. 12. A priming mixture for ammunition containingv 15% to 25% mercuryfulminate, 25% to 30% lead trinitroresorcinate, 28% to 40% barium nitrate, 5% to 8% lead peroxide and 12% to 15% calcium silicide.

13. A priming mixture for ammunition containing 15% to 25% mercury fulminate, 25% to lead trinitroresorcinate, 12% to 15% calcium silicide.

14. A containing 15% to 25% mercury fulminate, 25% to 30% lead trinitroresorcinate, and 5% to 8% lead peroxide. I

EDMUND 'voig HERZ.

riming mixture for ammunition 

